The invention relates to a printing unit for a press.
Printing units of web-fed rotary presses, in particular of newspaper presses, have a plurality of press units, each press unit comprising a transfer cylinder, a form cylinder and an inking unit and damping unit. Furthermore, such printing units can have impression cylinders, it being possible for an impression cylinder to interact with one or more transfer cylinders of different press units. In addition to printing units which have such impression cylinders, printing units which have no impression cylinder are also known, the transfer cylinders of two press units rolling on each other in such printing units without impression cylinders. The transfer cylinders are also designated blanket cylinders, and the form cylinders are also designated plate cylinders. The form cylinders or plate cylinders bear printing forms.
When printing with a printing form, a distinction is in principle drawn between methods which, on the one hand, operate with a printing form which can be written once and, on the other hand, operate with a rewritable printing form. Printing methods which use rewritable printing forms are also summarized under the keyword “computer to press/direct imaging”. The present invention relates to a printing unit for a press which operates with rewritable and erasable printing forms. The applicant markets digital presses which operate with rewritable and erasable printing forms, under the product description “DICOweb”.
The principles of the DICOweb technology are described in “Handbuch der Printmedien [Handbook of print media], Helmut Kipphan, pages 674 to 680, year 2000, Springer-Verlag”. Printing units which operate with such rewritable and erasable printing forms have, in addition to the subassemblies described above, at least one imaging device for imaging and/or de-imaging the rewritable and erasable printing forms positioned on the form cylinders.
Press units of web-fed rotary presses are increasingly being designed more compactly, that is to say with smaller dimensions. As a result, the overall room available on the printing units of a press is reduced, that is to say the space available for positioning and arranging the inking units, damping units and imaging devices. Furthermore, in the case of printing units having compact designs, access to the cylinders, specifically to the form cylinders and transfer cylinders, is made more difficult. In the case of printing units having small dimensions, the integration of inking units, damping units and imaging devices into the press while simultaneously ensuring simple access to the form cylinders and transfer cylinders of the printing units is already presenting considerable difficulties.
On this basis, the present invention is based on the problem of providing a novel type of printing unit for a press.
According to an embodiment of the invention, the inking unit, if appropriate together with the damping unit, can be pivoted with respect to a preferably fixed form cylinder from a printing position into a rest position, it being possible for the imaging device to be pivoted with respect to the preferably fixed form cylinder from an imaging position into a rest position, the imaging device being pivoted into a rest position when the inking unit and, if appropriate, damping unit is pivoted into the printing position and, when the imaging device is pivoted into the imaging position, the inking unit and, if appropriate, the damping unit being pivoted into a rest position. It is also possible for the inking unit and, if appropriate, the damping unit and also the imaging device to be pivoted into the respective rest position, simple access to the cylinders of the printing unit then being ensured.
In an alternative embodiment of a press unit according to the invention, by means of a translational relative movement between the form cylinder of each print unit and the corresponding imaging device, which movement runs in the direction of the longitudinal axis of the form cylinders, the respective press unit can be transferred from printing operation to imaging operation.
Both embodiments of the invention ensure simple integration of inking units, damping units and imaging devices in printing units of presses having compact designs. By means of translational or pivoting movements between the form cylinders and inking unit, damping unit and the imaging devices, the overall space available may be utilized optimally and, furthermore, simple access to the cylinders of the printing unit is ensured. In the sense of the present invention, either the, or each, imaging device can be moved toward the respective form cylinders of the printing unit or, on the other hand, the form cylinders can also be moved towards the, or each, imaging device. In this case, as mentioned, either translational or pivoting movements are utilized.